Microporous membranes have been known since old times (for example, R. Kesting, Synthetic Polymeric Membranes, McGraw Hill) and have widely served as filters and so forth.
The microporous membranes are used for the filtration and sterilization of washing water for electronics, water for pharmaceuticals, water for manufacturing processes of pharmaceuticals, and water for foods. In recent years, the application and consumption of the membranes are being expanded, and particularly, highly reliable microporous membranes receive attention and are in wide use for the purpose of capturing particles.